2-dialkylaminomethyl-5-methyl-1, 6 hexane diamines and related compounds



nited States Patent Pont de Nemours and Company, Wilmington, Del., acorporation of Delaware No Drawing. Application June 29, 1953, SerialNo. 364,944

9 Claims. '(Cl. 260-2475) This invention relates to new compositions ofmatter and to methods for their preparation.

Aliphatic diprimary diamines containing also tertiary amine functionsare a relatively unexplored class of polyamines. Typical of this classof polyamines is S-N-dimethylamino-l,6-diaminohexane,

which is obtained by reducing the adduct of 1,4-dicyano- 2-butene or itsisomer, 1,4-dicyano-1-butene, with a secondary aliphatic amine, asdescribed in U. S. 2,532,561. In this polyamine the tertiary aminonitrogen is linked directly to a chain carbon atom. This has resulted indisadvantages in certain polymer forming and polymer-modifyingapplications, and accordingly a need has arisen for diprhnary diamineshaving, in addition, tertiary amine functions which, however, are notdirectly attached to a chain carbon.

The present invention provides a new class of such amines. compoundsincludes'those carrying a tertiary amino nitrogen function formed byhydrogenation of the adducts of alpha-methylene-delta-methyladiponitrilewith acyclic, alicyclic, and heterocyclic secondary amines.

The new aliphatic tertiary amines of this invention are those which havetwo primary amino groups separated by a chain of six carbon atoms, andone tertiary amino nitrogen atom linked to the carbon chain through asingly bonded methylene group. The compounds to which the invention isdirected in particular embodiments are tertiary amines of the formulawherein R and R taken individually each represents a lower alkyl group,and taken together represent a divalent saturated aliphatic group whichconjointly with HN forms a heterocycle, e. g. a morpholino,thio-morpholino, piperazyl or piperidine ring.

The new tertiary-amino-nitrogen-containing aliphatic diprimary amines ofthis invention are readily prepared fromalpha-methylene-delta-methyladiponitrile-secondary amine type adducts,e. g. by reacting in 1:1 mole ratiosalpharnethylene-delta-methyladiponitrile with the desired secondaryamine, desirably in the presence of an inert solvent, and thenfractionally distilling and converting the dinitrile thus obtained tothe corresponding diamine by reduction, desirabiy by catalytichydrogenation in the presence of liquid ammonia over a base metalhydrogenation catalyst, such as alloy skeleton nickel or cobalt.

EXAMPLE 'I To a mixture of alpha-methylene-delta-methyladiponitrile (134g., 1 mole) and a33% aqueous solution of di- In particular'embodimentsthis novel class of ice methylamine (272 g., 2 moles) is added 200 cc.of dioxan to give a clear solution. This mixture is warmed for 30minutes on a steam bath and then distilled. After removal of a foreshot,there is obtained 150 g. of the adduct, B. P. 152156 C./4 mm., n 1.4519.

The above adduct (89.5 g., 0.5 mole) is transferred to a pressurereactor and hydrogenated in liquid ammonia (40 g.) over alloy-skeletoncobalt (10 g.) at C. and 2500 lb./sq. in. pressure for 1 hour.Distillation of the product gives 75.5 g. (87%) ofZ-dimethylaminomethyl- 5-methyl-1,6-hexanediamine, B. P. 116 C./4 mm.,12 1.4688, N. E. 62.6 (titration for primary amino groupstheory 62.3).

EXAMPLE H A mixture of alpha-methylene-delta-methyladiponitrile (67 g.,0.5 mole), 45 g. (0.52 mole) of morpholine, and about 0.1 g. of sodiumvmethoxide is refluxed at 160 C. for 1 hour and then cooled. It isextracted with ether, the ether extract washed with water and thenextracted with dilute hydrochloric acid. The acid extract is made basicwith sodium hydroxide and extracted with ether. Removal of ether gives21 g. (19%) of crude product. Distillation gives 13.5 g. of a compoundboiling at 197 C./4 mm., 11 1.4740.

The above adduct (31 g.) is hydrogenated over alloyskeleton cobalt (5g.) at C. and 2500 lbs/sq. in., pressure for 1 hour in 10 cc. of dioxanand 25 g. of liquid ammonia. There is obtained 27.8 g. (87%) of2-morpholinomethyl-S-methyl-l,6-hexanediamine, B. P. 169 C./6 mm.,.n1.4883, N. E. 114.1 (theory 114.5--titration for primary amino groups).Analysis shows the compound to contain 18.2% N, theory for C12H27N3O is18.4.

The alpha-methylene-delta-methyladiponitrile used in the above examplesis prepared as described in U. S. Patent 2,566,203.

The secondary amines added to thealpha-methylenedelta-methyladiponitrile are those of the general formulain which Rand R may be monovalent organic radicals or together may forma divalent organic radical Whose divalency emanates from differentcarbon atoms; R and R may be wholly hydrocarbon or may comprise abivalent chain of carbon atoms interrupted by oxygen, nitrogen, orsulfur. The alkyl groups may contain up to 18 carbon atoms, or more. Itis preferred that the alkyl groups be lower ,alkyl groups, i. e.,contain less than 6 carbon atoms. Especially useful and preferredcompounds are those in which .R and/ or R are methyl, ethyl, or propylbecause of their readily availability. When R and R are divalent organicradicals, it is preferred that they be radicals which form 5 and-6membered ring systems with the nitrogen. These rings may thus containonly carbon and nitrogen'or they may contain carbon, nitrogen, andoxygen or carbon, nitrogen, and sulfur.

Examples of secondary amines of the above types are climethylamine,methylethylamine, dicyclohexylamina'dioctylamine, didodecylamine,dioctadecylamine, methylethoxyethylam-ine, N-methylcyclohexylamine,morpholine, piperidine, piperazine, l-methylpiperazine, and the like.

The tertiary amino nitrogen-containing primary aliphatic amines of thisinvention have the two primary amino nitrogens separated by a chain ofcarbon atoms and the tertiary amino group linked to a chain carbonthrough a singly bonded methylene group. The two remaining valencesoftheter-tiary amino nitrogen atom are satisfied by the radicals R and Ras hereinabove defined.

A most significant advantage of the compositions of this invention overthe prior art compositions having tertiary nitrogen attached directly tothe chain of carbon atoms separatingthe NH2 groups resides in thethermal stability of the polyamides derived therefrom. The said priorart compositions upon conversion to polyadipamides or other polyamidesin the well-known manner yield products which break down at considerablylower temperatures than do the corresponding polyamides from thediamines herein disclosed. The explanation for this difierence may liein the fact that the prior art structure had a single hydrogen on thechain carbon to which the tertiary nitrogen was attached, while in thecomposition of this invention there is no hydrogen similarly disposed.

In the first column of the table below are listed secondary amines to besubstituted for the dimethylamine of Example I in the process of ExampleI to produce the adducts listed in the second column and the diamines tobe obtained by reduction of the adducts in accord with the process ofExample I in the third column.

Table 1 Secondary Amine Adduct Diamlne Dipropylamine 2-Dipropylamino-2-Dipropy]aminomethyl-5-methylmethyl-5-methy1-l adiponitrile.fi-hexane-diamine. Dihexylamine Z-Dihexylamlno-2-Dihexy1aminoethylmethyl-S-methyl- E-methyl-l, 6- adiponitrile.hexane-diamine. Dioctylamine 2-Dioctylamino-2-Dioctylaminomethyl-fi-methylmethyl-5-methyl-I adiponitrile.fi-hexane-diamine. Didodecylamine 2-Didodeeylamino-Z-Didodecylaminomethyl-S-methylmethyl-5-methyl-1, adiponitrile.G-hexane-diamine. Dio ctadeeylamine. 2-Dioctade cylamino- 2-Dioctadecylaminomethyl-5-methylmethyl-5-methyl-1, adipom'trile. G-hexanediamine.Methylethoxy-ethyl- 2-Methylethoxy- 2-Methylethoxyethy1- amine.ethyl-aminomethylaminoethyl-5- E-methyladiponimethyl-1, 6-

. trile. hexanediamine. 2-methylpiperidine 2-(2-Methylpiperi- 2-Z-Methylpiperidine) dine)-methyI-5- exanedlamine. methyladiponitrile.N-methylpiperazine. 2-(1-Methy1-1-piper- 2-(1-Methyl-1-piper- HazyDmethyl-5- azyl) methyl-54,6-

methyladiponitrile. hexanediamine Methylethylamine Z-Methylethylamino-2-methyleth laminomethyl 5-methylmethyl-fi-methyl-l adiponitrile.G-hexanediamine. N-methyIcyclo-hexyl- 2- '-Methylcycl0-Z-(N-Methylcyclcamine. hexyl-aminohexyl-amiuomethyD- methy1)-5-methyl-5-methy1-1, 6 adiponitrile. hexanediamine. Dicyclohexylamine-.2-Dicyelohexylamino- 2-Dicyclohexylaminomethyl fi-methylmethyl-5-methyl-1,

adiponitrile. 6-hexanedian1ine Z-(Benzhydryl-2-[2-(Benzhydrylz-[z-Benzhydrylmermercapto)-N- mercapto) N-capto-N-methylmethylethylamine. methylethylaminoethylaminomethyllmethyl]5-methy1- 5-methyl-1,6 adiponitrile. hexanediamine.

N, N, N-Triethyl- 2-(2-Diethylamiuo- 2-(2-Diethylaminoenediamine.ethyl-aminoethylaminomethyD- methyl)-5methyl- 5-methyl-1,6-adlponitrile. hexanediamine. Thlamorpholine 2-Ihiamorpholino-Z-Thiamorpholinometh I-S-methyl methyl-5-methyl-1, adiponitrile.fi-hexanedlamine.

In preparing the new aliphatic diamines of this invention, thealpha-methylene-delta-methyladiponitrile and secondary amine are mixedin approximately equimolar proportions and the mixture warmed on a waterbath. In some cases the use of a slight excess, e. g., of the order of 5to 10% by weight of one or the other reactants may be used. When theamine is low in cost as much as 0.5 to 5 molar excess may be used toinsure maximum conversion.

The reaction is generally complete in about an hour at temperatures inthe raneg of 80-110 C. If desired, however, it may be permitted to takeplace at room temperature but this prolongs the time of reaction andincreases costs.

Although the addition reaction occurs readily in the absence of addedcatalysts, in the case of amines which are feebly basic it may bedesirable to include a catalyst in the reaction mixture and thus reducethe time of reaction. Suitable catalysts are alkaline materials,particularly metallic alkoxides such as sodium and potassium alkoxides,and the like.

The reduction of the nitrile groups in thealphamethylene-delta-methyladiponitrile-secondary amine adduct may beelfected catalytically or chemically.

The chemical reduction can be effected with sodium and alcohol, withaluminum or lithium hydride, and the like.

The catalytic hydrogenation is performed under pressure at elevatedtemperatures in the presence of a hydrogenation catalyst known topromote the conversion of nitrile groups to primary amino groups.Suitable catalysts are nickel and cobalt, especially alloy-skeletonnickel and alloy skeleton cobalt.

The amount of catalyst, calculated as the metal, may range from 0.001 to15% by weight of the alpha-methylene-delta-methyladiponitrile-secondaryamine adduct. Since best results from the standpoint of reaction rateare achieved within the range of 1 to 10%, calculated on the same basisas above, this is the amount generally used. e

The chemical reduction is generally carried out by adding the reducingagent to a solution of the adduct in a suitable solvent at such rate asto maintain the reaction mixture below reflux.

For best results it is desirable to conduct the catalytic hydrogenationat aslow a temperature as possible, consistent with a practical rate ofreaction. In general, temperatures within the range of 50 to 200 C. areused but since the best over-all balance of yield of desired amine withreaction rate is obtained in the range of to C., this range embraces thepreferred operating conditions.

V The hydrogenation is effected at elevated pressures because this aidsin reducing the time of reaction and in improving the yield of desiredamine. Generally, pressures above 500 lb./sq. in. are used. Especiallyuseful are pressures in the range of 1000 to 5000 lbs/sq. in.

Although the use of a solvent is not essential, for most eflicientoperation it is desirable to perform the hydrogenation in the presenceof a solvent. Suitable solvents are alcohols, saturated hydrocarbons,anhydrous ammonia, etc.

The tertiary amino nitrogen containing aliphatic diamines of thisinvention are useful for conversion to polyamines, especially tofiber-forming polyamides possessing enhanced acid dyestuif uptake. Theyare also useful as intermediates for pharmaceuticals, insecticides, andother industrially useful products.

I claim: 1. A tertiary amine of the formula H2NCH: R

CCHz-N\ wherein R and R taken individually each represents a saturatedhydrocarbon group and taken together represent a divalent saturatedaliphatic group which conjointly with HN would form a 5 to 6 memberedring, said ring being further characterized in that it contains nomembers other than carbon, nitrogen, oxygen and sulfur, said ringcontaining from 4 to 5 carbon atoms, two of which are attached directlyto the nitrogen of the said HN group, said saturated hydrocarbon grouphaving not more than 18 carbon atoms.

2. A tertiary amine of the formula H2N CHj OH;

H C-CHr-N HzNCHgfiEHCHaC 7' CH;

3. A tertiary amine of the formula H=N-- JH CHaCE:

b-oHr-N mN-omoncmog omen,

wherein R and R taken individually each represents a saturatedhydrocarbon group and taken together represent a divalent saturatedaliphatic group which conjointly with HN forms a 5 to 6 membered ring,said ring being further characterized in that it contains no membersother than carbon, nitrogen, oxygen and sulfur, said ring containingfrom 4 to 5 carbon atoms, two of which are attached directly to thenitrogen of said HN group, said saturated hydrocarbon group having notmore than 18 carbon atoms.

5. Process of claim 4 wherein said secondary amine is a dialkyl amine.

6. Process of claim 4 wherein said secondary amine is morpholine.

7. Process of claim 4 wherein the said hydrogenation catalyst containscobalt as an active component.

8. Process of claim 7 wherein the temperature during hydrogenation isfrom to 200 C. and the pressure is above 500 lb./ sq. in.

9. Process of claim 7 wherein the temperature is from to and thepressure is above 500 lbs/sq. in.

References Cited in the file of this patent UNITED STATES PATENTS2,436,779 Senkus Feb. 24, 1948 2,532,277 Castle Dec. 5, 1950 2,532,561Langkammerer Dec. 5, 1950

1. A TERTIARY AMINE OF THE FORMULA